Switched Capacitor Voltage Converters

MAX828, MAX829
Switched Capacitor
Voltage Converter
The MAX828 and MAX829 are CMOS charge pump voltage
inverters that are designed for operation over an input voltage range of
1.15 V to 5.5 V with an output current capability in excess of 50 mA.
The operating current consumption is only 68 A for the MAX828 and
118 A for the MAX829. The devices contain an internal oscillator
that operates at 12 kHz for the MAX828 and 35 kHz for the MAX829.
The oscillator drives four low resistance MOSFET switches, yielding
a low output resistance of 26 and a voltage conversion efficiency of
99.9%. These devices require only two external capacitors, 10 F for
the MAX828 and 3.3 F for the MAX829, for a complete inverter
making it an ideal solution for numerous battery powered and board
level applications. The MAX828 and MAX829 are available in the
TSOP−5 package.
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TSOP−5
CASE 483
1
MARKING DIAGRAM
Features
EAx AYW G
G
• Operating Voltage Range of 1.15 V to 5.5 V
• Output Current Capability in Excess of 50 mA
• Low Current Consumption of 68 A (MAX828) or
•
•
•
•
1
EAx
= Device Code
x= A or B
A
= Assembly Location
Y
= Year
W
= Work Week
G
= Pb−Free Package
(Note: Microdot may be in either location)
118 A (MAX829)
Operation at 12 kHz (MAX828) or 35 kHz (MAX829)
Low Output Resistance of 26 Space Saving TSOP−5 Package
Pb−Free Packages are Available
Typical Applications
•
•
•
•
•
•
•
•
PIN CONFIGURATION
LCD Panel Bias
Cellular Telephones
Pagers
Personal Digital Assistants
Electronic Games
Digital Cameras
Camcorders
Hand−Held Instruments
Vout
1
Vin
2
C−
3
5
C+
4
GND
(Top View)
ORDERING INFORMATION
−Vout
Device
MAX828EUK
1
Vin
MAX828EUKG
MAX829EUK
4
MAX829EUKG
Figure 1. Typical Application
December, 2005 − Rev. 4
TSOP−5
3000 Tape/Reel
TSOP−5
(Pb−Free)
3000 Tape/Reel
TSOP−5
3000 Tape/Reel
TSOP−5
(Pb−Free)
3000 Tape/Reel
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.
This device contains 77 active transistors.
© Semiconductor Components Industries, LLC, 2005
Shipping †
5
2
3
Package
1
Publication Order Number:
MAX828/D
MAX828, MAX829
MAXIMUM RATINGS*
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁ
ÁÁÁ
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ÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
ÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
ÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
ÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁ
Rating
Symbol
Value
Unit
Input Voltage Range (Vin to GND)
Vin
−0.3 to 6.0
V
Output Voltage Range (Vout to GND)
Vout
−6.0 to 0.3
V
Output Current (Note 1)
Iout
100
mA
Output Short Circuit Duration (Vout to GND, Note 1)
tSC
Indefinite
sec
Operating Junction Temperature
TJ
150
°C
Power Dissipation and Thermal Characteristics
Thermal Resistance, Junction to Air
Maximum Power Dissipation @ TA = 70°C
RJA
PD
256
313
°C/W
mW
Storage Temperature
Tstg
−55 to 150
°C
Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit
values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied,
damage may occur and reliability may be affected.
*ESD Ratings
ESD Machine Model Protection up to 200 V, Class B
ESD Human Body Model Protection up to 2000 V, Class 2
ELECTRICAL CHARACTERISTICS (Vin = 5.0 V for MAX828 C1 = C2 = 10 F, for MAX829 C1 = C2 = 3.3 F, TA = −40°C to 85°C, typical
values shown are for TA = 25°C unless otherwise noted. See Figure 20 for test setup.)
Symbol
Min
Typ
Max
Unit
Operating Supply Voltage Range (RL = 10 k)
Characteristic
Vin
1.5 to 5.5
1.15 to 6.0
−
V
Supply Current Device Operating (RL = R)
TA = 25°C
MAX828
MAX829
TA = 85°C
MAX828
MAX829
Iin
Oscillator Frequency
TA = 25°C
MAX828
MAX829
TA = −40°C to 85°C
MAX828
MAX829
fOSC
Output Resistance (Iout = 25 mA, Note 2)
MAX828
MAX829
Rout
Voltage Conversion Efficiency (RL = R)
Power Conversion Efficiency (RL = 1.0 k)
A
−
−
68
118
90
200
−
−
73
128
100
200
kHz
8.4
24.5
12
35
15.6
45.6
6.0
19
−
−
21
54
−
−
26
26
50
50
VEFF
99
99.9
−
%
PEFF
−
96
−
%
1. Maximum Package power dissipation limits must be observed to ensure that the maximum junction temperature is not exceeded.
TJ + TA ) (PD RJA)
2. Capacitors C1 and C2 contribution is approximately 20% of the total output resistance.
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2
MAX828, MAX829
100
Figure 20 Test Setup
TA = 25°C
Rout, OUTPUT RESISTANCE ()
Rout, OUTPUT RESISTANCE ()
100
90
80
70
60
50
40
30
20
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Figure 20 Test Setup
80
70
60
50
40
30
20
1.0
5.5
1.5
2.0
Vin, SUPPLY VOLTAGE (V)
3.5
4.0
4.5
5.0
5.5
Figure 3. Output Resistance vs. Supply Voltage
MAX829
100
90
Figure 20 Test Setup
Vin = 1.5 V
Rout, OUTPUT RESISTANCE ()
Rout, OUTPUT RESISTANCE ()
3.0
2.5
Vin, SUPPLY VOLTAGE (V)
Figure 2. Output Resistance vs. Supply Voltage
MAX828
80
70
Vin = 2.0 V
60
50
Vin = 3.3 V
40
30
20
−50
Vin = 5.0 V
−25
0
25
75
50
Figure 20 Test Setup
90
Vin = 1.5 V
80
70
60
Vin = 2.0 V
50
Vin = 5.0 V
40
Vin = 3.3 V
30
20
−50
100
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
TA, AMBIENT TEMPERATURE (°C)
Figure 4. Output Resistance vs. Ambient
Temperature MAX828
Figure 5. Output Resistance vs. Ambient
Temperature MAX829
35
100
35
Figure 20 Test Setup
Figure 20 Test Setup
TA = 25°C
30
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
TA = 25°C
90
Vin = 4.75 V
Vout = −4.0 V
25
20
Vin = 3.15 V
Vout = −2.5 V
15
10
Vin = 1.9 V
Vout = −1.5 V
5
0
TA = 25°C
30
Vin = 4.75 V
Vout = −4.0 V
25
20
Vin = 3.15 V
Vout = −2.5 V
15
10
Vin = 1.9 V
Vout = −1.5 V
5
0
0
10
20
30
40
50
0
10
20
30
40
50
C1, C2, C3, CAPACITANCE (F)
C1, C2, C3, CAPACITANCE (F)
Figure 6. Output Current vs. Capacitance MAX828
Figure 7. Output Current vs. Capacitance MAX829
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Figure 20 Test Setup
TA = 25°C
350
Vin = 4.75 V
Vout = −4.0 V
300
250
Vin = 3.15 V
Vout = −2.5 V
200
150
Vin = 1.9 V
Vout = −1.5 V
100
50
0
0
10
20
30
350
Figure 20 Test Setup
TA = 25°C
300
Vin = 4.75 V
Vout = −4.0 V
250
200
Vin = 3.15 V
Vout = −2.5 V
150
100
Vin = 1.9 V
Vout = −1.5 V
50
0
0
10
20
30
40
50
C1, C2, C3, CAPACITANCE (F)
C1, C2, C3, CAPACITANCE (F)
Figure 8. Output Voltage Ripple vs.
Capacitance MAX828
Figure 9. Output Voltage Ripple vs.
Capacitance MAX829
130
RL = ∞
Figure 20 Test Setup
80
70
TA = 85°C
TA = 25°C
60
50
TA = −40°C
40
RL = ∞
Figure 20 Test Setup
120
Iin, SUPPLY CURRENT (A)
Iin, SUPPLY CURRENT (A)
50
40
90
30
110
TA = 85°C
100
90
TA = 25°C
80
70
TA = −40°C
60
50
20
1.5
fOSC, OSCILLATOR FREQUENCY (kHz)
Vout, OUTPUT VOLTAGE RIPPLE (mVpp)
400
2.0
2.5
3.0
3.5
4.0
4.5
40
1.5
5.0
2.0
2.5
3.0
3.5
4.0
4.5
Vin, SUPPLY VOLTAGE (V)
Vin, SUPPLY VOLTAGE (V)
Figure 10. Supply Current vs. Supply Voltage
MAX828
Figure 11. Supply Current vs. Supply Voltage
MAX829
13.0
fOSC, OSCILLATOR FREQUENCY (kHz)
Vout, OUTPUT VOLTAGE RIPPLE (mVpp)
MAX828, MAX829
Figure 20 Test Setup
12.5
Vin = 5.0 V
12.0
Vin = 3.3 V
11.5
11.0
Vin = 1.5 V
10.5
10.0
−50
−25
0
25
50
75
100
40
Figure 20 Test Setup
39
Vin = 3.3 V
38
37
Vin = 1.5 V
36
35
Vin = 5.0 V
34
33
32
−50
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
TA, AMBIENT TEMPERATURE (°C)
Figure 12. Oscillator Frequency vs. Ambient
Temperature MAX828
Figure 13. Oscillator Frequency vs. Ambient
Temperature MAX829
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4
5.0
100
MAX828, MAX829
0
0
Figure 20 Test Setup
Vout, OUTPUT VOLTAGE (V)
−1.0
Vin = 2.0 V
−2.0
Vin = 3.3 V
−3.0
−4.0
Vin = 5.0 V
−5.0
10
20
30
40
−2.0
Vin = 3.3 V
−3.0
−4.0
Vin = 5.0 V
−5.0
10
20
30
40
50
Figure 14. Output Voltage vs. Output Current
MAX828
Figure 15. Output Voltage vs. Output Current
MAX829
90
Vin = 5.0 V
80
70
Vin = 3.3 V
Vin = 1.5 V
Vin = 2.0 V
50
TA = 25°C
OUTPUT VOLTAGE RIPPLE & NOISE = 10 mV/Div.
AC COUPLED
Vin = 2.0 V
Iout, OUTPUT CURRENT (mA)
Figure 20 Test Setup
40
0
TA = 25°C
Iout, OUTPUT CURRENT (mA)
100
60
−1.0
−6.0
0
50
η, POWER CONVERSION EFFICIENCY (%)
−6.0
0
η, POWER CONVERSION EFFICIENCY (%)
TA = 25°C
10
20
30
40
50
100
Figure 20 Test Setup
90
Vin = 5.0 V
80
70
60
Vin = 3.3 V
Vin = 1.5 V
Vin = 2.0 V
50
TA = 25°C
40
0
10
20
30
40
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
Figure 16. Power Conversion Efficiency vs.
Output Current MAX828
Figure 17. Power Conversion Efficiency vs.
Output Current MAX829
Figure 20 Test Setup
OUTPUT VOLTAGE RIPPLE & NOISE = 10 mV/Div.
AC COUPLED
Vout, OUTPUT VOLTAGE (V)
Figure 20 Test Setup
Vin = 3.3 V
Iout = 5.0 mA
TA = 25°C
TIME = 25 s/div
Figure 18. Output Voltage Ripple and Noise
MAX828
Figure 20 Test Setup
Vin = 3.3 V
Iout = 5.0 mA
TA = 25°C
TIME = 10 s/div
Figure 19. Output Voltage Ripple and Noise
MAX829
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5
50
MAX828, MAX829
Charge Pump Efficiency
−Vout
C
+ 2
6
1
The overall power efficiency of the charge pump is
affected by four factors:
1. Losses from power consumed by the internal
oscillator, switch drive, etc. (which vary with input
voltage, temperature and oscillator frequency).
2. I2R losses due to the on−resistance of the MOSFET
switches on−board the charge pump.
3. Charge pump capacitor losses due to Equivalent
Series Resistance (ESR).
4. Losses that occur during charge transfer from the
commutation capacitor to the output capacitor when
a voltage difference between the two capacitors
exists.
Most of the conversion losses are due to factors 2, 3 and 4.
These losses are given by Equation 1.
RL
OSC
Vin
+
+
2
C1
C3
3
4
MAX828: C1 = C2 = C3 = 10 F
MAX829: C1 = C2 = C3 = 3.3 F
Figure 20. Test Setup/Voltage Inverter
DETAILED OPERATING DESCRIPTION
ƪ
The MAX828/829 charge pump converters inverts the
voltage applied to the Vin pin. Conversion consists of a
two−phase operation (Figure 21). During the first phase,
switches S2 and S4 are open and S1 and S3 are closed. During
this time, C1 charges to the voltage on Vin and load current
is supplied from C2. During the second phase, S2 and S4 are
closed, and S1 and S3 are open. This action connects C1
across C2, restoring charge to C2.
S1
P
+ I out 2
LOSS(2,3,4)
1
(f
OSC
)C1
) 8R
SWITCH
R out ^ I out 2
) 4ESR
C1
) ESR
C2
ƫ
(eq. 1)
The 1/(fOSC)(C1) term in Equation 1 is the effective output
resistance of an ideal switched capacitor circuit (Figures 22
and 23).
The losses due to charge transfer above are also shown in
Equation 2. The output voltage ripple is given by Equation 3.
S2
PLOSS + [ 0.5C 1 (Vin 2 * Vout 2)
Vin
) 0.5C2 (VRIPPLE 2 * 2VoutVRIPPLE)]
C1
fOSC
(eq. 2)
V
C2
S3
RIPPLE
+
Iout
(f
)(C )
OSC 2
) 2(I out)(ESR )
C2
(eq. 3)
S4
−Vout
f
Vin
From Osc
Vout
C1
C2
RL
Figure 21. Ideal Switched Capacitor Charge Pump
Figure 22. Ideal Switched Capacitor Model
APPLICATIONS INFORMATION
Output Voltage Considerations
REQUIV
The MAX828/829 performs voltage conversion but does
not provide regulation. The output voltage will drop in a
linear manner with respect to load current. The value of this
equivalent output resistance is approximately 26 nominal
at 25°C and Vin = 5.0 V. Vout is approximately −5.0 V at light
loads, and drops according to the equation below:
VDROP + Iout
Vin
Vout
R
Rout
EQUIV
+
f
1
C1
C2
RL
Figure 23. Equivalent Output Resistance
Vout + * (Vin * VDROP)
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MAX828, MAX829
Capacitor Selection
Voltage Inverter
In order to maintain the lowest output resistance and
output ripple voltage, it is recommended that low ESR
capacitors be used. Additionally, larger values of C1 will
lower the output resistance and larger values of C2 will
reduce output voltage ripple. (See Equation 3).
Table 1 shows various values of C1, C2 and C3 with the
corresponding output resistance values at 25°C. Table 2
shows the output voltage ripple for various values of C1, C2
and C3. The data in Tables 1 and 2 was measured not
calculated.
The most common application for a charge pump is the
voltage inverter (Figure 20). This application uses two or
three external capacitors. The capacitors C1 (pump
capacitor) and C2 (output capacitor) are required. The input
bypass capacitor C3, may be necessary depending on the
application. The output is equal to −Vin plus any voltage
drops due to loading. Refer to Tables 1 and 2 for capacitor
selection. The test setup used for the majority of the
characterization is shown in Figure 20.
Table 1. Output Resistance vs. Capacitance
(C1 = C2 = C3), Vin = 4.75 V and Vout = −4.0 V
As with any switching power supply circuit, good layout
practice is recommended. Mount components as close
together as possible to minimize stray inductance and
capacitance. Also use a large ground plane to minimize
noise leakage into other circuitry.
C1 = C2 = C3
(mF)
MAX828 Rout
(W)
MAX829 Rout
(W)
0.7
127.2
55.7
1.4
67.7
36.8
3.3
36
26.0
7.3
26.7
24.9
10
25.9
25.1
24
24.3
25.2
50
24
24
Layout Considerations
Capacitor Resources
Selecting the proper type of capacitor can reduce
switching loss. Low ESR capacitors are recommended. The
MAX828 and MAX829 were characterized using the
capacitors listed in Table 3. This list identifies low ESR
capacitors for the voltage inverter application.
Table 3. Capacitor Types
Manufacturer/Contact
AVX
843−448−9411
www.avxcorp.com
Table 2. Output Voltage Ripple vs. Capacitance
(C1 = C2 = C3), Vin = 4.75 V and Vout = −4.0 V
C1 = C2 = C3
(mF)
MAX828 Ripple
(mV)
MAX829 Ripple
(mV)
0.7
377.5
320
1.4
360.5
234
3.3
262
121
7.3
155
62.1
10
126
51.25
24
55.1
25.2
50
36.6
27.85
Part Types/Series
TPS
Cornell Dubilier
508−996−8561
www.cornell−dubilier.com
Sanyo/Os−con
619−661−6835
www.sanyovideo.com/oscon.htm
SN
SVP
Vishay
603−224−1961
www.vishay.com
593D
594
−Vout
OSC
+
Vin
5
1
Input Supply Bypassing
The input voltage, Vin should be capacitively bypassed to
reduce AC impedance and minimize noise effects due to the
switching internals in the device. If the device is loaded from
Vout to GND, it is recommended that a large value capacitor
(at least equal to C1) be connected from Vin to GND. If the
device is loaded from Vin to Vout a small (0.7 F) capacitor
between the pins is sufficient.
ESRD
+
+
2
3
4
MAX828: Capacitors = 10 F
MAX829: Capacitors = 3.3 F
Figure 24. Voltage Inverter
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MAX828, MAX829
The MAX828 / 829 primary function is a voltage inverter. The device will convert 5.0 V into −5.0 V with light loads. Two
capacitors are required for the inverter to function. A third capacitor, the input bypass capacitor, may be required depending
on the power source for the inverter. The performance for this device is illustrated below.
0.0
TA = 25°C
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
0.0
−1.0
−2.0
Vin = 3.3 V
−3.0
Vin = 5.0 V
−4.0
−5.0
−6.0
TA = 25°C
−1.0
−2.0
Vin = 3.3 V
−3.0
Vin = 5.0 V
−4.0
−5.0
−6.0
0
10
20
30
40
Iout, OUTPUT CURRENT (mA)
50
0
Figure 25. Voltage Inverter Load Regulation
Output Voltage vs. Output Current MAX828
10
20
30
40
Iout, OUTPUT CURRENT (mA)
50
Figure 26. Voltage Inverter Load Regulation
Output Voltage vs. Output Current MAX829
−Vout
5
1
+
Vin
+
5
1
OSC
OSC
+
2
2
3
4
3
4
+
+
MAX828 Capacitors = 10 F
MAX829 Capacitors = 3.3 F
Figure 27. Cascade Devices for Increased Negative Output Voltage
Two or more devices can be cascaded for increased output voltage. Under light load conditions, the output voltage is
approximately equal to −Vin times the number of stages. The converter output resistance increases dramatically with each
additional stage. This is due to a reduction of input voltage to each successive stage as the converter output is loaded. Note that
the ground connection for each successive stage must connect to the negative output of the previous stage. The performance
characteristics for a converter consisting of two cascaded devices are shown below.
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−1.0
−1.0
−2.0
−2.0
−3.0
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
MAX828, MAX829
A
−4.0
−5.0
B
−6.0
−7.0
−8.0
−9.0
−3.0
C
−4.0
−5.0
−6.0
D
−7.0
−8.0
−9.0
−10.0
−10.0
0
10
20
30
Iout, OUTPUT CURRENT (mA)
0
40
10
20
30
Iout, OUTPUT CURRENT (mA)
Figure 28. Cascade Load Regulation,
Output Voltage vs. Output Current MAX828
Figure 29. Cascade Load Regulation,
Output Voltage vs. Output Current MAX829
5
1
Curve
Vin (V)
Rout (W)
A
3.0
173
B
5.0
141
C
3.0
179
D
5.0
147
40
OSC
Vin
2
+
−Vout
+
+
3
+
+
4
MAX828: Capacitors = 10 F
MAX829: Capacitors = 3.3 F
Figure 30. Negative Output Voltage Doubler
A single device can be used to construct a negative voltage doubler. The output voltage is approximately equal to −2Vin minus
the forward voltage drop of each external diode. The performance characteristics for the above converter are shown below.
Note that curves A and C show the circuit performance with economical 1N4148 diodes, while curves B and D are with lower
loss MBRA120E Schottky diodes.
−2.0
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
0.0
−2.0
A
−4.0
C
B
−6.0
D
−8.0
TA = 25°C
−10.0
0
10
20
30
A
−4.0
B
−6.0
C
−8.0
D
TA = 25°C
−10.0
40
0
10
20
30
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
Figure 31. Doubler Load Regulation,
Output Voltage vs. Output Current MAX828
Figure 32. Doubler Load Regulation,
Output Voltage vs. Output Current MAX829
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40
MAX828, MAX829
Curve
Vin (V)
Diodes
MAX828
Rout (W)
MAX829
Rout (W)
A
3.0
1N4148
122
118
B
3.0
MBRA120E
114
106
C
5.0
1N4148
96
90
D
5.0
MBRA120E
91
87
5
1
OSC
Vin
+
−Vout
+
2
+
3
+
+
+
+
4
MAX828: Capacitors = 10 F
MAX829: Capacitors = 3.3 F
Figure 33. Negative Output Voltage Tripler
A single device can be used to construct a negative voltage tripler. The output voltage is approximately equal to −3Vin minus
the forward voltage drop of each external diode. The performance characteristics for the above converter are shown below.
Note that curves A and C show the circuit performance with economical 1N4148 diodes, while curves B and D are with lower
loss MBRA120E Schottky diodes.
0.0
−2.0
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
0.0
A
−4.0
C
−6.0
B
−8.0
D
−10.0
−2.0
A
−4.0
−6.0
B
−8.0
C
−10.0
−12.0
D
−12.0
TA = 25°C
TA = 25°C
−14.0
−14.0
0
10
20
30
40
0
10
20
30
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
Figure 34. Tripler Load Regulation,
Output Voltage vs. Output Current MAX828
Figure 35. Tripler Load Regulation,
Output Voltage vs. Output Current MAX829
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40
MAX828, MAX829
Curve
Vin (V)
Diodes
MAX828
Rout (W)
MAX829
Rout (W)
A
3.0
1N4148
259
246
B
3.0
MBRA120E
251
237
C
5.0
1N4148
209
198
D
5.0
MBRA120E
192
185
5
1
OSC
+
Vin
+
2
+
3
Vout
4
MAX828: Capacitors = 10 F
MAX829: Capacitors = 3.3 F
Figure 36. Positive Output Voltage Doubler
A single device can be used to construct a positive voltage doubler. The output voltage is approximately equal to 2Vin minus
the forward voltage drop of each external diode. The performance characteristics for the above converter are shown below.
Note that curves A and C show the circuit performance with economical 1N4148 diodes, while curves B and D are with lower
loss MBRA120E Schottky diodes.
10.0
10.0
D
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
D
8.0
C
6.0
B
4.0
A
8.0
C
6.0
B
4.0
A
TA = 25°C
TA = 25°C
2.0
2.0
0
10
20
30
40
0
10
20
30
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
Figure 37. Doubler Load Regulation,
Output Voltage vs. Output Current MAX828
Figure 38. Doubler Load Regulation,
Output Voltage vs. Output Current MAX829
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40
MAX828, MAX829
Curve
Vin (V)
Diodes
MAX828
Rout (W)
MAX829
Rout (W)
A
3.0
1N4148
32.5
32.2
B
3.0
MBRA120E
27.1
25.7
C
5.0
1N4148
26.0
25.1
D
5.0
MBRA120E
21.2
19.0
5
1
OSC
+
Vin
+
2
+
+
3
Vout
+
4
MAX828: Capacitors = 10 F
MAX829: Capacitors = 3.3 F
Figure 39. Positive Output Voltage Tripler
A single device can be used to construct a positive voltage tripler. The output voltage is approximately equal to 3Vin minus
the forward voltage drop of each external diode. The performance characteristics for the above converter are shown below.
Note that curves A and C show the circuit performance with economical 1N4148 diodes, while curves B and D are with lower
loss MBRA120E Schottky diodes.
14.0
14.0
D
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
D
12.0
10.0
C
8.0
B
6.0
4.0
12.0
10.0
C
8.0
B
6.0
4.0
A
TA = 25°C
A
TA = 25°C
2.0
2.0
0
10
20
30
40
0
10
20
30
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
Figure 40. Tripler Load Regulation,
Output Voltage vs. Output Current MAX828
Figure 41. Tripler Load Regulation,
Output Voltage vs. Output Current MAX829
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40
MAX828, MAX829
Curve
Vin (V)
Diodes
MAX828
Rout (W)
MAX829
Rout (W)
A
3.0
1N4148
110
111
B
3.0
MBRA120E
96.5
96.7
C
5.0
1N4148
84.5
87.3
D
5.0
MBRA120E
78.2
77.1
−Vout
+
5
1
5
1
OSC
Vin
OSC
2
+
2
3
4
3
4
+
+
MAX828 Capacitors = 10 F
MAX829 Capacitors = 3.3 F
Figure 42. Paralleling Devices for Increased Negative Output Current
An increase in converter output current capability with a reduction in output resistance can be obtained by paralleling two
or more devices. The output current capability is approximately equal to the number of devices paralleled. A single shared
output capacitor is sufficient for proper operation but each device does require it’s own pump capacitor. Note that the output
ripple frequency will be complex since the oscillators are not synchronized. The output resistance is approximately equal to
the output resistance of one device divided by the total number of devices paralleled. The performance characteristics for a
converter consisting of two paralleled devices is shown below.
−1.0
−1.0
TA = 25°C
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
TA = 25°C
B
−2.0
−3.0
A
−4.0
−5.0
−2.0
D
−3.0
C
−4.0
−5.0
0
20
40
60
80
100
0
20
40
60
80
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
Figure 43. Parallel Load Regulation, Output
Voltage vs. Output Current MAX828
Figure 44. Parallel Load Regulation, Output
Voltage vs. Output Current MAX829
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13
100
MAX828, MAX829
Curve
Vin (V)
Rout ()
A
5.0
13.3
B
3.0
17.3
C
5.0
14.4
D
3.0
17.3
Q2
5
1
−Vout
+
OSC
Vin
C1
Q1
C2
+
2
+
C3
3
C1 = C2 = 470 F
C3 = 220 F
Q1 = PZT751
Q2 = PZT651
4
−Vout = Vin −VBE(Q1) − VBE(Q2) −2 VF
Figure 45. External Switch for Increased Negative Output Current
The output current capability of the MAX828 and MAX829 can be extended beyond 600 mA with the addition of two
external switch transistors and two Schottky diodes. The output voltage is approximately equal to −Vin minus the sum of the
base emitter drops of both transistors and the forward voltage of both diodes. The performance characteristics for the converter
are shown below. Note that the output resistance is reduced to 0.9 and 1.0 ohms for the 828 and 829 respectively.
−2.0
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
−2.2
−2.4
−2.6
−2.8
Vin = 5.0 V
Rout = 0.9 TA = 25°C
−3.0
−3.2
0
0.1
0.2
0.3
0.4
0.5
0.6
−2.2
−2.4
−2.6
−2.8
Vin = 5.0 V
Rout = 1.0 TA = 25°C
−3.0
−3.2
0
0.1
0.2
0.3
0.4
0.5
Iout, OUTPUT CURRENT (A)
Iout, OUTPUT CURRENT (A)
Figure 46. Current Boosted Load Regulation,
Output Voltage vs. Output Current MAX828
Figure 47. Current Boosted Load Regulation,
Output Voltage vs. Output Current MAX829
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14
0.6
MAX828, MAX829
50
Q2
C1
Vout
5
1
+
50
OSC
+
Q1
Vin
C2
2
+
C3
3
Capacitors = 220 F
Q1 = PZT751
Q2 = PZT651
4
Figure 48. Positive Output Voltage Doubler with High Current Capability
The MAX828/829 can be configured to produce a positive output voltage doubler with current capability in excess of
500 mA. This is accomplished with the addition of two external switch transistors and two Schottky diodes. The output voltage
is approximately equal to 2Vin minus the sum of the base emitter drops of both transistors and the forward voltage of both
diodes. The performance characteristics for the converter are shown below. Note that the output resistance is reduced to 1.8.
9.0
Vin = 5.0 V
Rout = 1.8 TA = 25°C
8.4
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
8.8
8.0
7.6
7.2
6.8
0
0.1
0.2
0.3
0.4
0.5
8.2
7.8
7.4
7.0
0.6
Vin = 5.0 V
Rout = 1.8 TA = 25°C
8.6
0
0.1
0.2
0.3
0.4
0.5
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
Figure 49. Positive Doubler with Current
Boosted Load Regulation, Output Voltage vs.
Output Current, MAX828
Figure 50. Positive Doubler with Current
Boosted Load Regulation, Output Voltage vs.
Output Current, MAX829
−Vout
5
1
+
OSC
Vin
+
MAX828: Capacitors = 10 F
MAX829: Capacitors = 3.3 F
2
+
+
3
4
+
Figure 51. A Positive Doubler, with a Negative Inverter
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15
+Vout
0.6
MAX828, MAX829
All of the previously shown converter circuits have only single outputs. Applications requiring multiple outputs can be
constructed by incorporating combinations of the former circuits. The converter shown above combines Figures 24 and 36 to form
a negative output inverter with a positive output doubler. Different combinations of load regulation are shown below. In
Figures 52 and 53 the positive doubler has a constant Iout = 15 mA while the negative inverter has the variable load. In Figures 54
and 55 the negative inverter has the constant Iout = 15 mA and the positive doubler has the variable load.
9.5
Positive Doubler
Iout = 15 mA
9.0
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
9.5
8.5
−4.0
Negative Inverter
−4.5
−5.0
Negative Inverter Rout = 28.8 TA = 25°C
0
9.0
8.5
−4.0
Negative Inverter
−4.5
−5.0
10
20
30
Iout, NEGATIVE INVERTER OUTPUT CURRENT (mA)
Positive Doubler
Iout = 15 mA
Negative Inverter Rout = 28 TA = 25°C
0
Figure 52. Negative Inverter Load Regulation,
Output Voltage vs. Output Current, MAX828
Figure 53. Negative Inverter Load Regulation,
Output Voltage vs. Output Current, MAX829
9.5
9.5
Positive Doubler
Rout = 21.4 9.0
Vout, OUTPUT VOLTAGE (V)
Vout, OUTPUT VOLTAGE (V)
30
10
20
Iout, NEGATIVE INVERTER OUTPUT CURRENT (mA)
8.5
−4.0
Negative Inverter
−4.5
Negative Inverter Iout = 15 mA
TA = 25°C
9.0
8.5
−4.0
Negative Inverter
−4.5
Negative Inverter Iout = 15 mA
TA = 25°C
−5.0
−5.0
0
Positive Doubler
Rout = 20 10
20
30
Iout, POSITIVE DOUBLER OUTPUT CURRENT (mA)
0
Figure 55. Positive Doubler Load Regulation,
Output Voltage vs. Output Current, MAX829
Figure 54. Positive Doubler Load Regulation,
Output Voltage vs. Output Current, MAX828
+
10
20
30
Iout, POSITIVE DOUBLER OUTPUT CURRENT (mA)
IC1
C1
C2
Vin
GND
−Vout
C3
+
+
GND
0.5 ″
Inverter Size = 0.5 in x 0.2 in
Area = 0.10 in2, 64.5 mm2
Figure 56. Inverter Circuit Board Layout, Top View Copper Side
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16
MAX828, MAX829
PACKAGE DIMENSIONS
TSOP−5
CASE 483−02
ISSUE E
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. MAXIMUM LEAD THICKNESS INCLUDES
LEAD FINISH THICKNESS. MINIMUM LEAD
THICKNESS IS THE MINIMUM THICKNESS
OF BASE MATERIAL.
4. A AND B DIMENSIONS DO NOT INCLUDE
MOLD FLASH, PROTRUSIONS, OR GATE
BURRS.
D
S
5
4
1
2
3
B
L
G
A
DIM
A
B
C
D
G
H
J
K
L
M
S
J
C
0.05 (0.002)
H
M
K
MILLIMETERS
MIN
MAX
2.90
3.10
1.30
1.70
0.90
1.10
0.25
0.50
0.85
1.05
0.013
0.100
0.10
0.26
0.20
0.60
1.25
1.55
0_
10 _
2.50
3.00
INCHES
MIN
MAX
0.1142 0.1220
0.0512 0.0669
0.0354 0.0433
0.0098 0.0197
0.0335 0.0413
0.0005 0.0040
0.0040 0.0102
0.0079 0.0236
0.0493 0.0610
0_
10 _
0.0985 0.1181
SOLDERING FOOTPRINT*
0.95
0.037
1.9
0.074
2.4
0.094
1.0
0.039
0.7
0.028
SCALE 10:1
mm Ǔ
ǒinches
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal
Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
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For additional information, please contact your
local Sales Representative.
MAX828/D